// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/compositor/transform_animation_curve_adapter.h"

#include <sstream>

#include "base/time/time.h"
#include "cc/base/time_util.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "ui/compositor/test/test_utils.h"

namespace ui {

namespace {

    // Check that the inverse transform curve gives the gives a transform that when
    // applied on top of the parent transform gives the original transform
    TEST(InverseTransformCurveAdapterTest, InversesTransform)
    {
        gfx::Transform parent_start, parent_target;
        parent_start.Scale(0.5, 3.0);
        parent_start.Translate(-20.0, 30.0);
        parent_target.Translate(0, 100);

        gfx::Transform child_transform;
        child_transform.Rotate(-30.0);

        base::TimeDelta duration = base::TimeDelta::FromSeconds(1);

        const gfx::Transform effective_child_transform = parent_start * child_transform;

        TransformAnimationCurveAdapter parent_curve(gfx::Tween::LINEAR,
            parent_start,
            parent_target,
            duration);

        InverseTransformCurveAdapter child_curve(parent_curve,
            child_transform,
            duration);
        static const int kSteps = 1000;
        double step = 1.0 / kSteps;
        for (int i = 0; i <= kSteps; ++i) {
            base::TimeDelta time_step = cc::TimeUtil::Scale(duration, i * step);
            std::ostringstream message;
            message << "Step " << i << " of " << kSteps;
            SCOPED_TRACE(message.str());
            gfx::Transform progress_parent_transform = parent_curve.GetValue(time_step);
            gfx::Transform progress_child_transform = child_curve.GetValue(time_step);
            CheckApproximatelyEqual(effective_child_transform,
                progress_parent_transform * progress_child_transform);
        }
    }

} // namespace

} // namespace ui
